1 files changed, 10 insertions, 4 deletions
diff --git a/indra/newview/app_settings/shaders/class2/deferred/alphaV.glsl b/indra/newview/app_settings/shaders/class2/deferred/alphaV.glsl
index 9540ddd2e8..1586aab0f2 100644
--- a/indra/newview/app_settings/shaders/class2/deferred/alphaV.glsl
+++ b/indra/newview/app_settings/shaders/class2/deferred/alphaV.glsl
@@ -63,23 +63,29 @@ uniform vec3 light_direction[8];
 uniform vec3 light_attenuation[8]; 
 uniform vec3 light_diffuse[8];
 
+float calcDirectionalLight(vec3 n, vec3 l)
+{
+        float a = max(dot(n,l),0.0);
+        return a;
+}
+
 float calcPointLightOrSpotLight(vec3 v, vec3 n, vec4 lp, vec3 ln, float la, float fa, float is_pointlight)
 {
 	//get light vector
 	vec3 lv = lp.xyz-v;
 	
 	//get distance
-	float d = length(lv);
+	float d = dot(lv,lv);
 	
 	float da = 0.0;
 
 	if (d > 0.0 && la > 0.0 && fa > 0.0)
 	{
 		//normalize light vector
-		lv *= 1.0/d;
+		lv = normalize(lv);
 	
 		//distance attenuation
-		float dist2 = d*d/(la*la);
+		float dist2 = d/la;
 		da = clamp(1.0-(dist2-1.0*(1.0-fa))/fa, 0.0, 1.0);
 
 		// spotlight coefficient.
@@ -87,7 +93,7 @@ float calcPointLightOrSpotLight(vec3 v, vec3 n, vec4 lp, vec3 ln, float la, floa
 		da *= spot*spot; // GL_SPOT_EXPONENT=2
 
 		//angular attenuation
-		da *= calcDirectionalLight(n, lv);
+		da *= max(dot(n, lv), 0.0);		
 	}
 
 	return da;